Binding structure of refractory sleeve for inner hole of nozzle for continuous casting

Abstract

A bonding structure between a nozzle body of a continuous casting nozzle and a refractory sleeve inserted into the nozzle body, wherein the refractory sleeve contains 20 mass % or more of CaO. An adhesive including a mixture of a refractory aggregate and a binder is applied to a joint zone defined in either one of at least a portion of the outer peripheral surface of the refractory sleeve and at least a portion of the inner surface of the hollowed nozzle to which the refractory sleeve is attached, or between the inner surface of the nozzle body and the outer peripheral surface of the refractory sleeve inserted into the nozzle body. The adhesive is adjusted to have a porosity in the range of 15 to 90% after dried in the joint zone. The bonding structure has a function of relaxing a thermal stress due to exponential expansion of the refractory sleeve caused by molten steel flowing into an inner hole of the nozzle during use, so as to prevent the detachment of the refractory sleeve and adverse affects on the nozzle body due to thermal expansion of the refractory sleeve.

1. A bonding structure for a refractory sleeve attached to an inside of a continuous casting nozzle, said sleeve defining an inner hole of said nozzle, wherein
 said sleeve comprises 20 mass % or more of CaO; 
 said bonding structure comprises a joint formed by applying an adhesive to a joint zone defined by either one of at least a portion of an outer peripheral surface of said sleeve or an inner surface of a hollowed body of said nozzle to which said sleeve is attached, or defined by an inner surface between said hollowed body and an outer peripheral surface of said sleeve inserted into said hollowed body; 
 said adhesive comprises a mixture of a refractory aggregate containing 70 mass % or more of MgO as a primary component, said MgO having a particle size of 0.5 mm or less and a purity of 95% or more; and 
 said adhesive has a porosity of 30 to 75% after drying. 
 
   
   
     2. The bonding structure according to  claim 1 , wherein said adhesive comprises 30 mass % or less of alumina in the form of Al 2 O 3 . 
   
   
     3. A bonding structure for a refractory sleeve attached to an inside of a continuous casting nozzle, said sleeve defining an inner hole of said nozzle, wherein
 said sleeve comprises 20 mass % or more of CaO; 
 said bonding structure comprises a joint formed by applying an adhesive to a joint zone defined by either one of at least a portion of an outer peripheral surface of said sleeve or an inner surface of a hollowed body of said nozzle to which said sleeve is attached; 
 said adhesive comprises a mixture of a refractory aggregate containing 70 mass % or more of MgO as a primary component, said MgO having a particle size of 0.5 mm or less and a purity of 95% or more; and 
 said adhesive has a porosity of 30 to 75% after drying. 
 
   
   
     4. A bonding structure for a refractory sleeve attached to an inside of a continuous casting nozzle, said sleeve defining an inner hole of said nozzle, wherein
 said sleeve comprises 20 mass % or more of CaO; 
 said bonding structure comprises a joint formed by applying an adhesive to a joint zone defined by an inner surface between said hollowed body and an outer peripheral surface of said sleeve inserted into said hollowed body; 
 said adhesive comprises a mixture of a refractory aggregate containing 70 mass % or more of MgO as a primary component, said MgO having a particle size of 0.5mm or less and a purity of 95% or more; and 
 said adhesive has a porosity of 30 to 75% after drying.